Publication: Watching Agricultural Drought Worldwide - from Space
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Web: ... ISSN:
Year: 2014 ISBN:
Language: Inglés External Link: ...
Type: Abstract
In 2013, FAO GIEWS and the Climate, Energy and Tenure Division (NRC) have developed an “Agricultural Stress Index System” (ASIS) for detecting agricultural areas with a high likelihood of water stress (drought) on a global scale using remote sensing data with the technical assistance and advice from the Flemish Institute for Technological Research (VITO-TAP) and the Monitoring Agricultural Resources (MARS) unit of the Joint Research Centre (JRC) of EC. Data from NOAA-AVHRR and METOP-AVHRR (normalized difference vegetation index and brightness temperature) are used to calculate the per-pixel VHI on a global scale, averaged over the growing season. A phenological model, based on NDVI, is developed and employed to define the start and end of the growing season. Next, the averaged VHI over the growing season is aggregated over each administrative unit so the drought intensity can be assessed on a regional basis. The resulting data flow will provide timely and direct information on drought stress in all agricultural areas of the world. ASIS assesses the severity (intensity, duration and spatial extent) of the agricultural drought and indicates the final results at administrative level giving the possibility to compare it with the agricultural statistics of the country. Currently the ASIS database contains 30 years of agricultural hot spots data and information, starting from 1984. Since METOP imagery is only available for 2007 or later, the Flemish Institute for Technological Research (VITO), FAO’s partner in scientific and technical development, simulated METOP data into the NOAA-AVHRR time series through an “inter-calibration” study to obtain a time series from 1984 to 2013. The most affected year by drought of the time series is 1989 where most of the agricultural land suffered from water scarcity. At the end of the second ten day-period of August 2014 the most significant hot spots of the main crop season 2013/2014 were detected in, Central America, Colombia and Venezuela From the global version of ASIS designed for detecting agricultural hot spots on the globe, standalone versions are to be developed for monitoring the agricultural drought at country or regional level. The standalone version would be calibrated with local agricultural statistics and it would run using specific parameters, coefficients and mask of the main crops of the country or region. This version could also be used for pasture monitoring and for other risk management activities such as crop insurance.
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